Osmotic diaphragm



E. A. SPERRY.

OSMOTIC DIAPHRAGM.

APPLICATION FILED DEc.26, 1918.

Patented Feb. 8, v19.21.

- To all fw hom it ymay concern UNITEDSTATES forties.

,nimm A. spenen or 'BnooKLYNi NEW Yoan,"AssieNoRro-ANAGNDA I-.mn-PRODUCTS COMPANY, oF New Yoan, N. Y.,-A conroauroiii or DELAWARE.'

osn'orrc manuellen. 1

Be it known that' I, Emana A, .SPERRY, a citizen of the United States ofAmerica, residing at 1505 Alb'ermarle road,` Brooklyn, in the county ofKings and lState of New York, have invented certain new and usefulImprovements in Osmotic 41.3iaphragms,' of which the following is aspecification. i

This .invention relates to lporous' diaphragms forv use in-biiiuidcells. Morespe-v ciiically it relates, not only, to such diaphragms perse, but to a method of making4 an apparatus forusngthe same,

such diaphragme are capable of vwivde'appli# cation l will, to avoidlsurplusage, restrict the present disclosure Vprincipally to theapplication of the invention to apparatus .des

signed for use in the method of manufacturtrolysis. Such diaphragms. Incarrying ontthis'process considerable diiiiculty has been experienced inobtaining diaphrag'rns possessingthe necessary mechanical strength,ldurability-v and the proper degree 4or' porosity. Diaphragms consistingof paper, parchmentized or otherwise treated, have been triedas'hayealso others consisting of cloth treated '1n Various ways.V Noneoi` theseproved successi ful due to the fact thatthey not only lacked;`

' the desired mechanical strengthbut due also to the fact that thenecessary osmotic,jper colating, or combined;characteristics Were.-

lacking In fact until the present diaphragm' was invented it waspractically im possible to maintain a cell in uninterrupted"- operationfor more than a few days. By employing the diaphragm hereinafterdisclosed continuous operation .of many' 'weeks` has been attained. Y

One of the primary objects of the present?.

invention is to provide a durable diaphragm preferably osmotic having,the' proper qualities and possessing` greatl mechanical strength. l 1 zmethodis vdisclosed in the application for vUnited States Letters Patentby Ralph M. HarringtonHMethodof'producf' ing lead salts, Serialv No.193,415, filed Se ff tember 27, 1917. This method involves t eemployment ofa biiinid electrolytc-cell in: which the ano'lyte andcatholyte vare separati ed by a porous diaphragm orjs'eries of-snclihave shown an electrolytic celll comprising a specification@ Leitersratent. vP5,1;elntm1- 1reb, 8, 1921, .ippiicationgmeginecnibrjzs,19m/serial zee ,ai'sg lAnother object-is to `provide y a methodof.making 'andiisin'g-suchl diaphragms.- .A-further object-is to providean electrode which 'supports-the latter -in such a manner fas to preventriiptiir'e .thereof andshort-cir-- cuiting of the electrodes, and Whichsupports v .oneliof the electrodes. Further objects and advantages willappear -as 'hereinafter disclosed;

j vReferring .to .thedrawings trate what I now consider a'p'referredphy- 4sical embodiment oi' one-part of -my inven- 'Figurel is' a`somewhat diagrammatic sec-'i y y tional elevation of 'a hi'liiidejlectrolytif,` cell. ing white lead, or other lead salts, by elec-Fig.- 2 is-anenlarged sectional elevation vof onev ofthe electrodecompartments shown line' 4-4 of-.Fig 3.

the invention is V:which illus- 4 v Fig.'5 is a fragmentarysectional-detail of ,l

one'othe 'retaining bars employed.

Referring to Fig. 1, it'y will be seen-that .I

tank or container 1 in .which are mounted' a pliiralityof'spac'edanodeplates 2 between which Vare located aplnrality of 'cathodecompartments 3. Aj preferred form of such compartments vis illustratedlin Figs. '2, 3, and 4 `and may bev constructed.substantially asfollows. 1 A plurality of clamping frames, l

vpreferably of woodor other insulating material, are provlded themain'frame 5 being Urslia'pediii i'ormv and provided with guide I grooves V7fivhicli tliecathode 8 is adapted4 toentei. vTliegdiapliragins), Q areeach 'clamped between the main frame and one or the other .ofthe sidelframes 4:, 6. Thelattei` are closed frames 'and are ldetachablysecu-red to the mainframe 'and toeach `other by means of bolts 10." Inorder tov prevent :leakage .of liquid, cloth or other stiipsofcompressihle'material -11 may `he provided sure, of the catholyte and toprevent contact betweenthe diaphragms, the anode and cathode Which wouldgive rise to a short cirlcuit. These bars may comprise-4 an inner core.of steel coated with a layer of hard rub- 1 ber or other insulatingmaterial. A.

The diaphragms preferably consist. of parchmentized cloth or fabric.`One method of makingl one of such diaphragms, especially adapted' foruse in an electrolytic cell in the manufacture of white lead, isasfollows. A piece of duck canvas of suitable I f size and preferably ofcomparatively line weave is first freed of grease and other impurities.This ymay be .accomplished by boiling it in a weak solution, say aboutone per cent. solution of sodium hydrate for about ten minutes. -Thefabric may then be washed, boiled inl a weak solutionof hydrochloric orother acid for about ten minutes, t0 neutralize the caustic'solution,and then washed and dried. The fabric is now ready for parchmentizing-which may be accomplished as follows.

The fabric is subjected to a strongsulfuric acid bath, of say 1.750specific gravity,

for a .lengthV of time depending on .the osmotic and imperviousproperties desired. The extent of the anastomosingof the `weave `may bevariedof course `by changing the length of time of the bath or byotherwise varying the process. 4If it is desired to form It has beenfound in practice that osmotic diaphragme made in accordance with themethod set forth above, swell when moist,

and tend to crack and tear `when allowed to 'become dry, causingtearing'of diaphragm away fromthe frames. It is, therefore, im-

portant that they be kept wet, moist or damp both before and after theyare mounted on the frames. This may preferably be accomplished bykeeping them in water until ready to be placed into the cells. When thediaphragms are in the cell the problem of preventing tearing andcracking/is more diiiicult. If it were possible to keep the upper edgeof the diaphragms submerged or flush with the surface of either or bothof the electrolytes, said diaphragms would never become dry. Itis,however, ractically impossible to do this. 4Isolve t e problem bypredetermined level.

\ tive and that the invention can allowing theupper end of thediaphragms to project above the surface-of the electrolyte, as shown inFig. 2 in which the dotted line represents the electrolyte level, and byproviding means to prevent the exposed crunimmersed portion frombecoming dry. This means may assume various forms, one form beingillustrated-in Figs. 2 and 8.

The upper edge of eachdiaphragm is made sufficiently long to lap overthe upper edge of the -corresponding side frame 4 or 6. A strip of cloth14, vpreferably having` capillary or absorbent properties, is placedover each of said upper edges and may, if desirable, Vbe stitched orotherwise secured to the corresponding diaphragm. These strips 14lshould be of sufiicient area to cover completely the unimmersedportions of the diaphragms. It willfbe obvious that if the vcloth V14 iskept wet or moist, so also will the unimmersed portions of thediaphragme. One

"method of keeping the said cloth 14 moist is by applyingglycerin to it.Another and preferable method is to allow the lower edge,

or edges, of said cloth to project into one or both of the electrolytesand thus convey liquidto the unimmersed portions of the vdiaphragms 9 bycapillary attraction. The fabric so used should, of course, be treatedto prevent deterioration in the electrolyte used.

Any suitable form of means may be employed to maintain the catholyte, e.the liquid in the cathode compartment, at its For reasons which Will beapparent on inspection of said p'rior application as well as the presentapplication I prefer to employ the system shown somewhatdiagrammatically in Fig. 3. The catholyte is continuously introducedinto each cathode compartment by means of a long tube 20 which `extends`into and substantially to the bottom of said compartment. The'latter isprovided-also with anV overflow pipe 22 which empties into a trough V`23 from which the catholyte is removed at .24.` Obviously the lliquidwithin thecompartment will never rise aboye the level of the overflowtube 22. i

In accordance with the provisions of the Vpatent statutes, I have hereindescribed. the

principle of operation of my invention, together with the apparatus,which I now consider to are resent the best embodiment thereof, but

desire to have it understood that the apparatus shown is only illustraecarried out by othermeans. Also, while it is designed to luse thevarious features and elements in the combination and relationsdescribed, some of these may be altered and others omitted withoutinterfering with the more `general results outlined, and the inventionextends to such use.

Having described my invention, what I claim and desireI to secure byLetters `Patent is:

1. A porous diaphragm for use in a bifluid cell,L-sa1d diaphragmconsisting of cloth parchmentized to a predetermined extent.I

A2. An osmotic diaphragm .for'use in an electrolytic cell, saiddiaphragm consisting of cloth parchmentized to a predetermined extent. y

3. j combination, a parchmentized dlai phragm for a biiiuid cell andmeans for preventingthe unimmersed portion of said diaphragm frombecoming dry. f

4. An electrolytic cell comprising a parchmentizedv fibrous diaphragmand means forI automatically conve ing 'moisture to the unimmersedportion o Said diaphragm to prevent the latter from becoming dry.

5. An electrolytic cell comprising a parchmentized diaphragm and meansfor automatically conveying electrolyte to the unimmersed portion ofsaid diaphragm to prevent the latter from becoming dry.

6. An electrolytic cell comprising a parchmentized diaphragm andcapillary means for automatically conveying electrolyte to Atheunimmersed portion of said diaphragm to'prevent the latter from becomingdry.

7. An electrode compartment comprising a plurality of diaphragm-clampingframes and a plurality of retaining bars secured thereto across theopen-space thereof.

8. An electrode compartment comprising a main frame, a plurality ofdiaphragmclamping frames, one for each side of said main frame andelectrode-guide means on said main frame.

9. vAn electrode compartment comprising a main frame and side frames, aplurality of diaphragms eachclamped between said main frame andacorresponding side frame and a luralityof retaining-bars carried by4each si e frame between the latter and the corresponding diaphragm.

l0. An electrode compartment comprising a main frame and side frames, aplurality of diaphragms each clamped between said main frame and a`corresponding side frame, electrode guide means on said mam frame, and

' a plurality of retaining bars carried by each side frame between thelatter and the corresponding diaphragm.

11. An electrode compartment comprising a main frame, a plurality ofdiaphragm'- clamping frames, one for each side of said main frame,electrode-guide means on said main frame,l and a diaphragm` supportingstrip at the top of the frame.

12. An electrode compartmentcomprising a main lframe, a plurality ofdiaphragmclamping frames, one for each side'of said main frame,electrode-guide means on said main` frame, and a diaphragm supporting vstrip at the top of the frame on each side lsaid `diaphragm in stretchedposition, and

absorbent material covering the upper portion of said diaphragm.

I In testimony whereof I have aiiixed my signature.

vELMER A. sPERRY.

